Hi. Really sorry to hear that and it's an ongoing struggle on our ward too. In fact I feel like the majority of people's issues (outside of severe mental illness) would resolve if their phone was taken for 6 months.
When you say comitted, was she definitely comitted? (Under section / sectioned) . Usually we try to aim for them to be in hospital voluntarily if possible. If they're voluntary we can't just take phones away as we'd have no legal grounds to do that.
If she was under section, then it is technically possible, but usually very hard to justify. When we section someone, everything has to be done according to the "least restrictive principle" which is to treat whilst restricting as few liberties as possible. Taking the phone away can be tricky under least restrictive principle. Most patients also need their phone to communicate with mental health advocates, solicitors, family, loved ones, make sure someone's looking after the house or pets or kids etc. If we were caught taking phones away, and the daily mail got hold of that, could you imagine what narrative could be spun that we're sectioning people and taking their phones away so they can't tell anyone about it? etc.
So yeah, very challenging unfortunately but completely agree they are usually doing far more harm than good from a social media / groupchat POV. We even have a large group of local EUPD women trying to get admitted at the same time in the same hospitals so they can be on the ward together